Devices of this type are used in systems for compensating silver-weight fluctuations and quality-data acquisition on machines producing fibre slivers and serve to keep the yarn-fineness fluctuations so small that they do not cause any disturbance in the finished fabric. The main differences in known regulating systems are in the measuring member, of which essentially three types are known, namely the so-called active-pneumatic measuring member, the roller-measurement system and the fibre-pressing system. With respect to the first two measuring members, attention is drawn to the USTER News Bulletin No. 30, 1982, and with respect to the last-mentioned measuring member, attention is directed to U.S. Pat. No. 4,864,853.
Common to all of the various measuring members is the fact that, on the one hand, in addition to the dependence on the fibre-silver mass, they also have further, usually negligible dependencies relevant to textiles. On the other hand, these measuring members allow only the measurement of the fibre-silver mass. When a further property of the fibre silver is to be monitored or measured, it is then necessary to use an additional measuring member which, however, as a rule has to be located at another measuring point as a result of space constraints.